Systems and methods for making customized arthroplasty jigs are disclosed in these three U.S. patent applications: U.S. patent application Ser. No. 11/656,323 to Park et al., titled “Arthroplasty Devices and Related Methods” and filed Jan. 19, 2007; U.S. patent application Ser. No. 10/146,862 to Park et al., titled “Improved Total Joint Arthroplasty System” and filed May 15, 2002; and U.S. patent Ser. No. 11/642,385 to Park et al., titled “Arthroplasty Devices and Related Methods” and filed Dec. 19, 2006. The disclosures of these three U.S. patent applications are incorporated by reference in their entireties into the present patent application.
As explained in U.S. patent application Ser. No. 11/656,323, a medical imaging system (e.g., a magnetic resonance imaging (“MRI”) system, a computed tomography (“CT”) system, etc.) is employed to generate multiple two-dimensional (“2D”) images of a joint region of a patient. The multiple 2D images or image slices of the patient's joint region are compiled via a computer program into three-dimensional (“3D”) bone and/or bone-cartilage models for use in creating customized arthroplasty jigs.
Creating the 2D images or image slices via CT imaging is relatively quick, but involves multiple scans, thus increasing the dose of radiation to a patient. Also, CT imaging requires the use of a contrast agent, which may cause an adverse reaction in some patients. Finally, CT imaging does not provide the image resolution offered by MRI.
MRI provides preferred resolution, as compared to CT imaging, allowing for the examination of soft tissue changes associated with OA, including changes to cartilage, bone, ligaments, meniscus, etc. Recent advances in MRI technology have enabled researchers to evaluate cartilage damage and progression over the cross-sectional and longitudinal planes of a joint. Unlike CT imaging, MRI involves no radiation dose.
Unfortunately, conventional MRI is not quick, requiring a patient to maintain a position completely still for 30, 45 or more minutes in order to obtain image slices that have adequate resolution. It is often extremely difficult, if not impossible, for a patient to remain completely still in any position, much less one that is often unnatural and/or difficult to maintain because of pain, fatigue, tremors and/or age.
Because of the difficulty in maintaining a position without movement for the long time period needed to obtain MRI image slices that are of adequate resolution for 3D modeling purposes, the MRI process often has to be repeated for a patient. Repeating the MRI process increases costs associated with making customized arthroplasty jigs and the lead-time needed for the manufacture of the customized arthroplasty jigs before performing the arthroplasty procedure.
There is a need in the art for a MRI system and method that improves the likelihood a MRI procedure will result in MRI image slices that are useable for the generation of 3D bone models used in the generation of customized arthroplasty jigs.